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CVE-2021-36740
Varnish Cache, with HTTP/2 enabled, allows request smuggling and VCL authorization bypass via a large Content-Length header for a POST…
Medium6.5EPSS 1.6%
- Published
- Updated
- Reserved
- Assigned by
- mitre
Description
Varnish Cache, with HTTP/2 enabled, allows request smuggling and VCL authorization bypass via a large Content-Length header for a POST request. This affects Varnish Enterprise 6.0.x before 6.0.8r3, and Varnish Cache 5.x and 6.x before 6.5.2, 6.6.x before 6.6.1, and 6.0 LTS before 6.0.8.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 1.6% · top 24% of all CVEs (5 Nov 2026)
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.
Weakness
Affected products
n/a
- affected n/a
References (7)
- https://varnish-cache.org/security/VSV00007.html (opens in a new tab)x_refsource_MISCx_transferred
- https://docs.varnish-software.com/security/VSV00007/ (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/varnishcache/varnish-cache/commit/9be22198e258d0e7a5c41f4291792214a29405cf (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/varnishcache/varnish-cache/commit/82b0a629f60136e76112c6f2c6372cce77b683be (opens in a new tab)x_refsource_MISCx_transferred
- FEDORA-2021-36e10d3f9f (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- FEDORA-2021-cf7585f0ca (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- DSA-5088 (opens in a new tab)vendor-advisoryx_refsource_DEBIANx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2021-36740)Record last updated .